Prior art prosthetic implant techniques have typically required the surgeon to align prosthetic components by eye. Use of this prior art technique in hip replacement surgery, for example, may result in misalignment of prosthetic components such as femoral stems and acetabular cups. This misalignment may lead to post operative complications such as misalignment of the leg, incorrect leg length and/or incorrect soft tissue tension. The long term effects of misaligned prosthetic components can also include accelerated wear of the components, aseptic loosening of the components and potentially early repetition of the surgery.
Some of these issues are at least partially addressed by the arrangement disclosed in co-pending patent application No. PCT/AU02/01482 (WO03/037192) the contents of which are hereby incorporated in their entirety by reference. This patent specification discloses the use of an alignment handle as shown in FIGS. 20 to 24 and FIG. 36.
This alignment handle has a gauge adapted to indicate whether a prosthetic component is in a predefined orientation. This alignment handle, whilst a significant improvement over the prior art, nevertheless exhibits certain limitations.
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.